1. Field of the Invention
This application relates to the field of high-temperature ovens and more particularly to the field of a door for a high-temperature oven.
2. Description of Related Art
High-temperature ovens, in particular laboratory high-temperature ovens, have an interior which can be heated to high temperatures. Drying ovens, for example, are operated with temperatures up to 300.degree. C. In this connection, difficulties are presented, in particular, by the thermal insulation of the door of these appliances. While the inside of the door assumes the high temperature of the interior of, for example, up to 300.degree. C., the outside of the door should remain as cold as possible, preferably under 50.degree. C.
In known high-temperature ovens, the door therefore comprises an external door which is composed, for example, of galvanized powder-coated steel sheet and an internal door which is preferably composed of stainless-steel sheet. The external door and the internal door are thermally isolated as far as possible, for which purpose the thermally conducting contacts between the internal door and external door are kept as small as possible.
In the case of a high-temperature oven disclosed in DE 41 18 800 C3 of the generic class mentioned at the outset, the external door is folded for this purpose at its external periphery to form a casing-type circumferential frame. The internal door is inserted into the frame in such a way that a circumferential separating gap remains free between the external edge of the internal door and the frame of the external door. It is only the four corners that the internal door is joined to the frame of the external door by internal door carriers and held. The internal door carriers form the sole thermally conducting joint between internal door and external door. As a result of the small cross section of the internal door carriers, a very small thermally conducting contact is consequently produced between internal door and external door.
In the case of this known door, the internal door carriers are formed by metallic lugs which are screwed or welded, on the one hand, to the internal door and, on the other hand, to the external door. The screwing or welding of the metal lugs is an additional working step in the production of the high-temperature oven.
It is therefore desirable to improve a high-temperature oven of the generic class mentioned at the outset so that the production becomes less expensive while desirable properties are retained or improved.